var BackgroundLayer = cc.Layer.extend({
  ctor: function(){
    this._super();
    this.init();
  },
  init: function(){
    this._super();

    var centerPos = cc.p(winSize.width / 2, winSize.height / 2);
    var spriteBg = cc.Sprite.create(s_PlayBG);
    spriteBg.setPosition(centerPos);
    this.addChild(spriteBg);
  }
});